Universal RNG

A collection of efficient pseudo-random number generators (PRNGs) implemented in pure Rust. This crate provides a wide variety of algorithms, ranging from standard Mersenne Twister to modern high-performance generators like Xoshiro and Philox.

Installation

Add this to your Cargo.toml:

[dependencies]
urng = "0.4.9"

Supported Generators

Generators are divided into two categories: standard generators and AVX-accelerated SIMD generators. Standard generators implement either the Rng32 or Rng64 trait (or return fixed-size arrays for counter-based variants). AVX generators expose a bulk-generation API and are listed separately.

32-bit Generators (urng::rng32)

Struct	Algorithm	Period / State
Mt19937	Mersenne Twister	$2^{19937}-1$
Sfmt607	SFMT	$2^{607}-1$
Sfmt1279	SFMT	$2^{1279}-1$
Sfmt2281	SFMT	$2^{2281}-1$
Sfmt4253	SFMT	$2^{4253}-1$
Sfmt11213	SFMT	$2^{11213}-1$
Sfmt19937	SFMT	$2^{19937}-1$
Sfmt44497	SFMT	$2^{44497}-1$
Sfmt86243	SFMT	$2^{86243}-1$
Sfmt132049	SFMT	$2^{132049}-1$
Sfmt216091	SFMT	$2^{216091}-1$
Sfc32	SFC32	$2^{127}-1$
Sfc32x4	SFC32 x4	$2^{127}-1$
Pcg32	PCG-XSH-RR	$2^{64}$
Philox32x4	Philox 4x32	-
SplitMix32	SplitMix32	$2^{32}$
Xorwow	XORWOW	$2^{192}-2^{32}$
Xorshift32	Xorshift	$2^{32}-1$
Xorshift128	Xorshift128	$2^{128}-1$
Xoshiro128Pp	xoshiro128++	$2^{128}-1$
Xoshiro128Ss	xoshiro128**	$2^{128}-1$
Xoroshiro64Ss	xoroshiro64**	$2^{64}-1$
Lcg32	LCG	$m$
Threefry32x4	Threefry 4x32	-
Threefry32x2	Threefry 2x32	-
Squares32	Squares	-
Jsf32	JSF32	-

64-bit Generators (urng::rng64)

Struct	Algorithm	Period / State
Xoshiro256Pp	xoshiro256++	$2^{256}-1$
Xoshiro256Ss	xoshiro256**	$2^{256}-1$
SplitMix64	SplitMix64	$2^{64}$
Sfc64	SFC64	$2^{256}$ approx
Mt1993764	Mersenne Twister 64	$2^{19937}-1$
Sfmt1993764	SFMT 64	$2^{19937}-1$
Philox64	Philox 2x64	-
Xorshift64	Xorshift64	$2^{64}-1$
Xoroshiro128Pp	xoroshiro128++	$2^{128}-1$
Xoroshiro128Ss	xoroshiro128**	$2^{128}-1$
TwistedGFSR	TGFSR	$2^{800}$ approx
Cet64	CET	$2^{64}$
Cet256	CET	$2^{256}$
Lcg64	LCG	$m$
Threefish256	Threefish-256	-
Biski64	Biski64	$2^{64}$

SIMD Generators (AVX)

These generators expose a bulk-generation API and require AVX support at runtime.

AVX2 (avx2)

Struct	Algorithm	Output
Sfc32x8	SFC32 x8	8×u32
Jsf32x8	JSF32 x8	8×u32
Xoroshiro64Ssx8	xoroshiro64** x8	8×u32

AVX-512 (avx512f)

Struct	Algorithm	Output
Pcg32x8	PCG-XSH-RR x8	8×u32
Philox32x4x4	Philox 4x32 x4	16×u32
SplitMix32x16	SplitMix32 x16	16×u32
Squares32x8	Squares x8	8×u32
Xoshiro128Ppx16	xoshiro128++ x16	16×u32
Xoshiro128Ssx16	xoshiro128** x16	16×u32
Jsf32x16	JSF32 x16	16×u32
Sfc32x16	SFC32 x16	16×u32
Xoroshiro64Ssx16	xoroshiro64** x16	16×u32
Xoshiro256Ssx2	xoshiro256** x2	2×u64
Sfc64x8	SFC64 x8	8×u64
Cet64x8	CET64 x8	8×u64
Cet256x2	CET256 x2	2×u64
Biski64x8	Biski64 x8	8×u64

Sampler

Requires the sampler feature.

Weighted random index selection. Two implementations are provided for each bit-width, both implementing the Sampler32 / Sampler64 trait (urng::sampler).

Struct	Module	Algorithm	Build	Sample
Bst32	urng::sampler32	Cumulative BST	O(n)	O(log n)
Alias32	urng::sampler32	Walker's Alias	O(n)	O(1)
Bst64	urng::sampler64	Cumulative BST	O(n)	O(log n)
Alias64	urng::sampler64	Walker's Alias	O(n)	O(1)

SeedGen

Requires the seedgen feature.

Hardware-noise-assisted seed generation. Wraps an existing Rng32/Rng64 and mixes in hardware noise (RDSEED/RDRAND on x86/x86_64, timestamp fallback elsewhere) via a Murmur3-style hash.

Struct	Module	Input RNG	Output
SeedGen32	urng::seedgen	Rng32	(u32, u32) pair
SeedGen64	urng::seedgen	Rng64	(u64, u64) pair

next_seed_pair() returns (raw, processed) — the raw hardware value and the mixed seed.

Usage Examples

Most generators expose the same basic workflow: create an instance with new, then use nextu, nextf, randi, randf, or choice depending on the output type you need. SIMD and counter-based generators return fixed-size arrays instead of single values.

Basic Usage

use urng::prelude::*;

fn main() {
    // 1. Initialize with a seed
    let mut rng = Xoshiro256Pp::new(12345);

    // 2. Generate random numbers
    let val_u64 = rng.nextu();
    println!("u64: {}", val_u64);

    let val_f64 = rng.nextf(); // [0.0, 1.0)
    println!("f64: {}", val_f64);

    // 3. Generate within a range
    let val_range = rng.randi(1, 100);
    println!("Integer (1-100): {}", val_range);

    // 4. Seeding with SplitMix64 (common pattern)
    // If you need to seed a large state generator from a single u64
    let mut sm = SplitMix64::new(9999);
    let seed_val = sm.nextu();
    let mut rng2 = Xoshiro256Pp::new(seed_val);
}

C ABI

This crate exports a C-compatible ABI generic interface. Each generator has corresponding:

• _new
• _free
• _next_uXXs (bulk generation)
• _next_fXXs (bulk generation)
• _rand_iXXs (bulk generation)
• _rand_fXXs (bulk generation)

Example for Mt19937:

void* mt19937_new(uint32_t seed, size_t warm);
void mt19937_next_u32s(void* ptr, uint32_t* out, size_t count);
void mt19937_rand_f32s(void* ptr, float* out, size_t count, float min, float max);
void mt19937_free(void* ptr);